TECHNOLOGY Automation
Double the Grip Worm Gear Screw Jacks Manufactured with Flexible Automation
A new manufacturing cell that includes milling, loading, and unloading, plus clamping technology and sensors for improved reliability facilitates the production of worm gear screw jacks considerably.
In the past, the production of worm gear screw jacks – electromechanical actuators that convert a rotary motion into a linear motion – was a laborious process for the Austrian manufacturer Zimm. For example, the individual components used to be clamped manually onto pallets. This procedure was both time-consuming and had high production costs. A project by the Lindau-based automation specialist Vischer & Bolli Automation and its cooperation partner proves that it can also be simplified. Together they developed a flexible manufacturing cell for about 30 different types of screw jacks. In addition to a five-axis milling machine from Grob, which ensures that high-precision components are created from the raw material, two Kuka robots are used here, which take over the loading and unloading of the fixtures and workpieces with their subsequent finishing in a fully automated manner in a modular production cell. The specially adapted clamping technology and sensors from Vischer & Bolli Automation guarantee reliable processing in the cell and machine. 20
Bespoke Gripper Solution for the Robots
For the special gripping tasks in the robot cell, the responsible person at Vischer & Bolli Automation, Marcel Haltiner, fell back on a long-standing partner: the system technology department of the gripper specialist Zimmer Group from Rheinau, Germany. It is one of the world‘s leading specialists when it comes to customized solutions. With its system solutions, the company´s system technology department can, among other things, optimally equip any robot make – including Kuka robots, of course - and significantly increase their functionality and efficiency. For the production plant at Zimm the department developed a special version of a double gripper with servo technology. This can grip components of all types and different geometries. It has a stroke of 150 mm and a holding force of 5000 Nm or 3000 Nm with a secured hold via a trapezoidal threaded spindle in the event of an unforeseen power failure. In addition, the clamping pressure on the gripper can be variably programmed for each workpiece.
Fully Automatic Operation
Almost all tasks that previously had to be carried out by hand at Zimm are now performed fully automatically by a KR Quantec and a KR Agilus from Kuka. The five-axis milling machine is supplied with raw material via a lift system. To do this, the employees load trays inside a huge lift system which projects four meters into the production hall. There is enough space to store raw material and finished parts here, also the clamping devices and, if necessary, tools are stored in this lift system. Afterwards, everything is automated. A special gripper, which is docked to the KR Quantec robot via the V&B zero-point clamping system, first removes the trays filled with raw parts (aluminum and cast cubes) in various sizes from the lift system in the robot cell and places them on an attachment table. Then the robot uses the Zimmer gripper to automatically position four raw parts in the Vischer & Bolli fixture and inserts them into the milling machine. „The machine can produce about 30 different components in batch sizes
messtec drives Automation 8/2021
